labtech1122

On 10/03/2023 at 07:06, Mr H in Yorkshire said:

Speaking as someone who was a New Member only a couple of months back I can say this is a fun and info packed place to enjoy. North Yorkshire, definitely God's Country.

Cheers

Good afternoon I'm going to Yorkshire dales on the 8th of May for a personal retreat away with my telescope for a few days. Lovely place

Also this is using DDS

16 hours ago, Elp said:

Did you use a filter? What calibration frames did you apply? Sometimes this sort of thing happens if your flats haven't been calibrated properly hence the over correction.

Adam Block's got some good videos discussing this on YT.

Hi, no filters have been used. The first image is with no calibration frames and after a dynamic background im PI the final is with dark and flats. It end up like the final image if I put any calibration frames in, I have tried doing one tried them all (bias, darks, flat light and flat dark) I have tried doing all together. I've deleted the registration files and started again and it still does it.

I have been able to get an ok image without the calibration frames but I can't avoid the rings I get in the image (like picture 1) even if I don't do background extraction and just edit the image I still get rings. This is an image I got near to ok (although by the end of the process I lost all colour) but you can see there are still rings around the image

hi, please can someone help.

when i go into pixinsight and go to either dynamic or automatic background extraction it always comes up like this in the end.

attached is the image before, the background removed and the image after

i have also included what happens to my image when i stack it with the flat, it seems to well over correct and remove alot of the galaxy too

Hi, is there any star parties this year around the Midlands area in the uk? I live near peterborough but don't mind travelling a distance to get places

This is my first image of these galaxies after some head scratching with pixinsight I got an image I'm quite happy with. I'm going to do another session with better focus and more subs but so far I'm happy

Hi, why is my pixinsight making the image look like this after doing any kind of background extraction? I've tried dynamic and automatic, filled lots of videos and went with loads of different settings but it either doesn't touch the image or it well over does it  (the multiple rings)

On 21/02/2023 at 11:31, wimvb said:

Don’t know about the eq35, but I’ve done and undone the upgrade for my eq3-pro. The problem is that the bearings are thicker than the teflon washers they are meant to replace, and the worm gear end block doesn’t really fit to the housing anymore. I didn’t see an improvement with the bearings, so removed them again.

OK great, thanks. What lube did you use to assemble it again?

1 hour ago, Adam J said:

Its a reflection from a curved surface from the sensor or the filter. You can tell as its distorted and offset from the star. The reducer would be the primary culprit for me. 

Adam 

Are there easy ways of removing it or is it a job for post processing?

1 hour ago, michael8554 said:

"doesn't pointing the telescope at the sun damage it? "

Point the FR at the sun, not the telescope !

Only damage might be to the wall ....... 😆

Michael

Haha yea that makes sense 🤣 

Hi, I've seen a video of someone stripping down and replacing the plastic washers in the eqm35 mount and replacing them with bearings. 

Has anyone done this before?

They have listed the parts needed for this upgrade (it's a really good video BTW with a very detailed way of stripping the mount)

22 hours ago, michael8554 said:

At the risk of rekindling an ages-long argument about the BF of Meade, Celestron, and clone FR's:

The #93633-A Celestron T-Adapter SC, the T- Ring, and Canon 650d, should give you 105mm back focus.

Try that and tweak by a few mm's if it's not perfect.

Michael

Thats what I have been using but all my stars on the edges have rotational trails. I've managed to master up a total length of 87mm so I'm going to try that and see what happenes then buy the appropriate adapters. I can just see my self getting the adapters and not having the right ones. Measure twice, buy once haha

8 minutes ago, michael8554 said:

Doing my own searches, the Antares may be one of the 85mm BF items

Measure the focal length by focusing the sun on an outside wall.

If it's about 240mm then BF is 105mm

If it's about 110mm FL the BF is 85mm

Michael

Might be a stupid thing to say but doesn't pointing the telescope at the sun damage it? Excuse my ignorance haha

On 20/12/2010 at 15:36, BlueAstra said:

My 'working distance' survey says:

Meade 4000 x0.63, 45mm

Celestron x0.63, 105mm (x0.7 @ 50mm, x0.5 @ 225mm)

OpticStar x0.63, 105mm (same as Celestron?)

Antares x0.63, ?mm

TelVue TRF2008 x0.8, 56 +/- 4mm

This may be of interest:

Weasner's Telescope Accessory Reviews

I'm having this issue at the moment with not actually knowing the BF of the antares FR 😕 I've been using 105mm but rotational star trails at the edges suggesting its too far away. I've managed to get it down to 87mm with the e tra buts I have have but not tested yet

ive had a play and managed to get 87mm BF, thats the minimum i can get with the bits i have. the only issue is instead of the t2 adpter its on a 1 1/4" t-piece. will the smaller ID result in less light to the sensor?

also you would happen to know the correct or where i cand the correct BF for the ntares x0.63 FR do you?

at the moment i have it pretty well balanced but have very little room to move further down. the only thing that does change the balance is the guide scop is in the 2 oclock posion on the telescope with refernce to where it attaches on the mount so its heavier one side than the other. not sure if thats a problem though or how to change it, i dont hae any other mounting points on the telescope

1 minute ago, Elp said:

You can try binning the guidecam X2, might help a little. Guiding also has a lot to do with your settings and the seeing on the night.

I've got the same Dec balancing issue but am working on a counterweight solution up front.

i havent really had an issue with the guiding in all fairness, i will try binning at x2, how do i do that on phd2?

ah yes nice idea, i would do that but it would over weight the mount

10 minutes ago, Elp said:

I seriously doubt it, at bare minimum I work at 1/3 but it boils down to the imaging/resolving scale of the camera which is connected to the guidescope and whether it matches the imaging train.

In simple terms I think of it this way, if you're looking at something in the far far distance (say a person standing still and they take a sidestep), to your eyesight they might not have moved, but if you look through binoculars or something similar you'll likely see the movement, same principle with monitoring a starfield rotation.

You'll also see this visually when looking through a short focal length telescope and a long one like yours and you're not sidereal tracking, in the longer one stars will move more frequently and faster, so your guidescope needs to be able to pick up on this and send commands to your mount.

"In the past, before the age of computers and digital cameras, astro images would use a guidescope that was about 1/3rd the focal length of a telescope for visual guiding with the human eye. So when talking to older Astro- imagers, you may still hear this recommendation. For example, if your telescope has a focal length of 1500mm, older astrophotographers may recommend guide scopes with a focal length of 500mm. However, digital cameras today are much more sensitive than the human eye and most guide cameras can detect apparent deviations in the guide star of about 0.1 pixels on average. So assuming that you want to detect a tracking error with a sensitivity up to1 pixel, a soft rule of thumb would be to select a guide scope with a focal length that is at least about 1/10th the size of your imaging scope"

9 minutes ago, Elp said:

I seriously doubt it, at bare minimum I work at 1/3 but it boils down to the imaging/resolving scale of the camera which is connected to the guidescope and whether it matches the imaging train.

In simple terms I think of it this way, if you're looking at something in the far far distance (say a person standing still and they take a sidestep), to your eyesight they might not have moved, but if you look through binoculars or something similar you'll likely see the movement, same principle with monitoring a starfield rotation.

You'll also see this visually when looking through a short focal length telescope and a long one like yours and you're not sidereal tracking, in the longer one stars will move more frequently and faster, so your guidescope needs to be able to pick up on this and send commands to your mount.

would having a barlow on the guide scope work? just spitting ideas

2 minutes ago, Elp said:

I seriously doubt it, at bare minimum I work at 1/3 but it boils down to the imaging/resolving scale of the camera which is connected to the guidescope and whether it matches the imaging train.

In simple terms I think of it this way, if you're looking at something in the far far distance (say a person standing still and they take a sidestep), to your eyesight they might not have moved, but if you look through binoculars or something similar you'll likely see the movement, same principle with monitoring a starfield rotation.

You'll also see this visually when looking through a short focal length telescope and a long one like yours and you're not sidereal tracking, in the longer one stars will move more frequently and faster, so your guidescope needs to be able to pick up on this and send commands to your mount.

ok fair enough, i think having a 500mmFL refractor on the side would look mental and put the mount well over its weight. i was looking at off axis guiding but this puts more weight on the back end of the image train and ive got the scope nearly as far as it goes on the dovtail to balance as it is, i dont think i would be able to balance it with added bits on the back

my The imaging / guiding ratio is 1:2.2

"A small 150-200mm guide scope should work up to 1,500 to 2,000mm focal length telescopes" i quoted this from google, is that right?

i was haing a look at what you said about the guide scope not being enough, i just read that for a focal length of 1500mm main scope a 150mm+ guide scope will be fine. so with the reducer i hae just under 1000mm FL and the guide scope is 240mm FL. in yoour opionion is 240mm enough?

or maybe this one? what is the correct thread and pitch of the back of the celestron 6" sct telescope